Suhaimi Illias
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Preferred name
Suhaimi Illias
Official Name
Suhaimi, Illias
Alternative Name
Ilias, Suhaimi
Illias, S.
Bin Illias, Suhaimi
Iliasb, Suhaimi
Main Affiliation
Scopus Author ID
54920300100
Researcher ID
ABB-5405-2020

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The role of gas-phase dynamics in interfacial phenomena during few-layer graphene growth through atmospheric pressure chemical vapour deposition

2020-02-14 , Fauzi F.B. , Ismail E. , Syed Abu Bakar S.N. , Ismail A.F. , Mohamed M.A. , Md Din M.F. , Suhaimi Illias , Ani M.H.

The complicated chemical vapour deposition (CVD) is currently the most viable method of producing graphene. Most studies have extensively focused on chemical aspects either through experiments or computational studies. However, gas-phase dynamics in CVD reportedly plays an important role in improving graphene quality. Given that mass transport is the rate-limiting step for graphene deposition in atmospheric-pressure CVD (APCVD), the interfacial phenomena at the gas-solid interface (i.e., the boundary layer) are a crucial controlling factor. Accordingly, only by understanding and controlling the boundary-layer thickness can uniform full-coverage graphene deposition be achieved. In this study, a simplified computational fluid dynamics analysis of APCVD was performed to investigate gas-phase dynamics during deposition. Boundary-layer thickness was also estimated through the development of a customised homogeneous gas model. Interfacial phenomena, particularly the boundary layer and mass transport within it, were studied. The effects of Reynolds number on these factors were explored and compared with experimentally obtained results of the characterised graphene deposit. We then discussed and elucidated the important relation of fluid dynamics to graphene growth through APCVD.

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Electrochemical Monitoring of Oxygen Potential on Fe-Cr Alloy Surface During High Temperature Oxidation in Dry and Humid Conditions

2023-01-01 , Ani M.H. , Purwanto H. , Musa M. , Suhaimi Illias , Kaderi A. , Salim N. , Rahim M.H.A. , Sutjipto A.G.E.

The formation of an external Cr2O3 scale is important to obtain the oxidation resistance of Fe–Cr alloys at high temperatures. It is well known that the critical concentration of Cr to form a protective external scale of Cr2O3 in humid conditions is higher than that in dry conditions, and the criterion is expressed as Wagner’s equation (Rapp in Acta Metall 9:730, 1961) [1]. A lot of mass gain data and metallographic surveys are required to determine the above criterion experimentally. A method of continuous monitoring of surface oxygen potential by oxygen concentration cell using stabilized zirconia has been applied to the oxidation of Fe-Cr alloy in order to check the protectiveness of the scale. The objective of this study is to measure surface oxygen potentials on Fe-0-17 wt% Cr alloys in Ar-21% O2 gas in dry condition and Fe-10-22 wt% Cr alloys in Ar-20% O2-20% H2O gas in humid condition at 1073 K up to 20 ks. In dry condition, the surface oxygen potentials of Fe with more than 10 wt% Cr alloys were close to the oxygen potential of the atmosphere immediately after the heating period. It indicates that a protective Cr2O3 scale formed on these alloys at the early stage of oxidation. However, the surface oxygen potentials of these same composition alloys were lower in humid conditions than that in dry, which suggests a higher oxidation rate. This paper demonstrated that the protectiveness of scales formed on Fe–Cr alloys can be evaluated in situ in a few hours, which is beneficial to assess the high temperature oxidation of metals.

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Metal Dusting Led Failure in a High-Temperature Condenser

2023-01-01 , Kaderi A. , Bakar S.N.S.A. , Ani M.H. , Suhaimi Illias , Osman M.S.

Corrosion is a metallurgical problem that occurs frequently in a power plant, plant inevitable, especially in the present days, since higher efficiency of a power plant is required and thus the process temperature is increasing. Choosing the right materials for pipeline is very crucial since it is affecting the service life and operational reliability. The research is done to study the oxidation behaviour of ferritic alloy for power plant. A failed component from a gas combined cyclic thermal power plant was received and a failure analysis is done to investigate the cause of failure of the equipment. Results from the analysis suggested that the pipe was exposed to high temperature oxidation and metal dusting. Metal dusting mechanism and how it affects materials in high temperature condition is then identified and explained in this work.

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Thermal and Static Properties Investigation of Different Intake Manifold Materials to Lower Air Intake Temperature for Improved Engine Performance

2023-04-01 , Halim S.S. , Md. Tasyrif bin Abdul Rahman , Abdul Hamid Adom , Mohd Al-Hafiz Mohd Nawi , Mohd Ridzuan Mohd Jamir , Suhaimi Illias

Formula SAE competition is targeted at students who are interested in designing and developing a Formula-type race car. Rules were imposed to restrict the car’s performance for safety besides encouraging problem-solving skills. One such rule is the requirement of a 20mm restrictor inserted between the carburettor and intake manifold to reduce the air intake. With a constricted airflow creating a bottleneck effect, less air will be provided to the engine for combustion, consequently reducing engine efficiency. The purpose of this project is to overcome this problem despite the restriction imposed by the rules. This is done by choosing an intake manifold material that provides a low air temperature while withstanding the stress and vibrations from the engine. Computational Fluid Dynamics (CFD) software was used to conduct the static, thermal and modal analysis of Aluminium Alloy 6063, Gray Cast Iron, Fibreglass Epoxy and Carbon Fibre Epoxy to choose the material that produces lower intake air temperature while maintaining high strength. Carbon fibre epoxy was found to provide the best durability against static stress while maintaining a lower intake air temperature compared to the other materials tested.

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Effect of Oxygen Gas Exposure on T91 Alloy at High Temperature Oxidation of Steam Reformer

2023-01-01 , Rosdin M.R.H. , Ismail A.A.M. , Hamid A.M.A. , Purwanto H. , Suhaimi Illias , Bakar S.N.S.A. , Ani M.H.

Steam-Methane Reforming (SMR) is one of the most economical ways to produce hydrogen from natural gas. Steam reforming industry is hugely relied on using supercritical power plant where the working temperature of the plant must exceed 600 °C. Along with the high operating temperature, the situation promotes the acceleration of high temperature oxidation. This will cause fouling and spalling of oxide scales at the boiler tube. Eventually, fouling will reduce heat transfer between the tube and steam generated, causing a higher temperature is needed to produce steam. Until now, the only approach used by the industry is to manually replace the corroded boiler tube. Other than that, many studies have been conducted on the behavior of boiler tubes at temperatures exceeding 800 °C. However, to our knowledge, no study has been done to investigate the air electrolyte substrate interfacial electrochemical reaction at high temperature. This project was carried out to investigate the corrosion potential of T91 boiler tube at 650 °C for 2 h, 8 h, and 12 h, measure the current density (Icorr) by calculating corrosion potential (Ecorr) value using Tafel Extrapolation and determine the oxidation potential of oxygen gas at 650 °. The oxide layer thickness at exposed temperature was determined to measure the oxidation kinetics. The study concludes that there was an increase of 8.49% in current conductivity between the blank experiment and T91 alloy oxidation potential test. The oxidation process was following the parabolic rate law which manifest that the corrosion is controlled by ionic diffusivity in the oxide layer. The oxide layer formed on the sample has an average thickness of 54.10 μm and this value can be used to calculate the oxidation kinetics of the sample using parabolic rate constant, Kp, resulting with the value of 6.78 × 10−14 m2/s.

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Review on performance of lithium titanate and its impurities dopant as a lithium-ion battery anode

2024-03 , Eva Nurhaliza , Muhammad Asri Idris , Norsuria Mahmed , M. Komiyama , Nur Farhana Diyana Mohd Yunos , Suhaimi Illias

Li-ion batteries are the main source of energy for electronic devices such as cameras, calculators, mobile phones, laptops, and electric vehicles. Among the materials being considered, lithium titanate (𝐿𝑖4𝑇𝑖5𝑂12) has become a promising anode material due to its high stability and safety, as well as enabling high operability without sacrificing lifetime. However, in order to further improve performance and customise properties for specific applications, impurity dopants have been investigated as a means of modifying 𝐿𝑖4𝑇𝑖5𝑂12 performance. This paper examines 𝐿𝑖4𝑇𝑖5𝑂12 and its impurities as anode materials. Starting with a basic understanding of the crystal structure and characteristics of 𝐿𝑖4𝑇𝑖5𝑂12, its properties and applications. Besides, this study explores the effects of different dopants on the 𝐿𝑖4𝑇𝑖5𝑂12 on battery parameters. Based on various research studies and recent developments, the review summarises the current knowledge about 𝐿𝑖4𝑇𝑖5𝑂12 and impurity dopants. Each dopant's different effects on the lattice structure highlight its importance for further development. As a result, it may lead to future research of 𝐿𝑖4𝑇𝑖5𝑂12 anodes for large-scale energy storage technology.

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Maximum spreading diameter of a water droplet after impact on a hot surface beyond Leidenfrost temperature

2023-01-01 , Juhar M.Z.F. , Muhammad Sofwan Mohamad , Suhaimi Illias , Nasrul Amri Mohd Amin , Suhaila Hussain , Ani M.H.

The impact of liquid droplets on heated surfaces are relevance across a range of applications. The maximum spreading diameter of water droplet during impact on hot surface was experimentally studied. The surface was made of aluminium. The diameter and height of the aluminium block was 70.0 mm and 30.0 mm, respectively. During experiment, the test surface was heated beyond Leidenfrost temperature. A high-speed video camera was used to capture the droplet images from the first impact until the droplet reached maximum spreading condition. The frame rate was set to be 2,000 fps. Distilled water was used as the test liquid. The impact height was set to be about 65.0 mm. From the high-speed images analysis, the droplet diameter was found to be approximately 4.5 mm. The measured droplet maximum spreading diameters were found to have a good agreement with theoretical calculation.

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Slagging of Coal Blends: Comparison between Pre-Blended and in Furnace Blend

2020-07-09 , Somad Abdul Latiff A. , Musa M. , Anhar Z. , Suhaimi Illias , Ani M.H.

Coal blending technique in electric generating power plant has been widely used to reduce coal consumption cost. However, due to various coals from different places blended together, it had caused problems. Slagging formed during the operations can reduced boiler efficiency, resulting high costs for maintenance caused by blockage, corrosion and erosion. Many empirical indices and predictive method have been developed to minimize these problems but most are unreliable for coals from different places and many predictive methods are carried out in different environment. In this research, the method starts from fabricating the pre-blended and in furnace blend techniques at a local coal pulverized power plant. After feeding the coal blends for coal trial burn, the resulting ash deposition are collected at the burner where slagging usually occurs. The raw coals in used and the slagging samples are then characterized and determine their crystalline phase and compositions by using X-Ray Diffraction (XRD) and Sacnning Electron Microscope Energy Dispersive Xray (SEM/EDX). From XRD analysis, compounds such as quartz, cristobalite low and manganosite were found as main species in ash deposition at all location of collected slagging. However, there are also some compound exist at specific location with specific technique being used. In the burner area for pre blended technique, compound Al2SiO5, Mg2Al4Si5, KNO2 and FeO was found, whereas in furnace blend K2Mn2(SO4)3 was found. At bottom part of the furnace, pre-blended graphite was presence and in furnace yield MnO2 and Al2SiO5. At top part where superheater reside, the existence of mullite, Al2(Al2.5Si1.5)9.75 was found for pre-blended technique and microcline, KAlSiO3O8 is observed from in furnace blend technique. From the EDX analysis, in furnace technique shows more complete combustion and feasible for less slagging inside the furnace compared to pre-blended technique.

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High Temperature Oxidation of T91 Alloy of Steam Reformer

2023-01-01 , Rosdin M.R.H. , Ismail A.A.M. , Hamid A.M.A. , Purwanto H. , Suhaimi Illias , Bakar S.N.S.A. , Ani M.H.

Steam plays a significant role in the reforming process of hydrogen. It is generated in a waste heat recovery unit at temperature of 650 ℃. Along with the high operating temperature, the situation promotes acceleration of high temperature oxidation. This will cause fouling and spalling of oxide scales at the boiler tube. Eventually, fouling will reduce heat transfer between the tube and steam generated, causing a higher temperature is needed to produce steam. Until now, the only approach used by the industry is to manually replace the corroded boiler tube. Other than that, many studies have been conducted on the behavior of boiler tubes at temperatures exceeding 800 °C. However, to our knowledge, no “in-situ” study has been done to investigate the high temperature electrochemistry aspect of boiler tubes. A review conducted by B.A Pint [1] in his paper mentioned that it is notoriously difficult to imitate the harsh environments in laboratory scale. Popov [2] stated that the only available method to decrease corrosion rate at high temperature corrosion and hot corrosion is only by implementing protective coatings. This project was carried out to investigate the corrosion potential of T91 boiler tube at 650 °C for 30 min, 1 h, 2 h, 8 h, and 12 h, measure the current density (Icorr) by calculating corrosion potential (Ecorr) value using Tafel Extrapolation and determine the current conductivity of oxygen gas at 650 ℃. Apart from that, the oxide layer thickness at exposed temperature is also determined to measure the oxidation kinetics. The study concludes that there was an increase of 8.49% in current conductivity between the blank experiment and T91 alloy conductivity test. The oxide layer formed on the sample is significant to calculate the oxidation kinetics of the sample using parabolic rate constant (Kp), resulting with the value of 6.78 × 10–14 m2s−1.

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The Performance of Thermosetting Plastic Waste Reinforced Sustainable Brick

2023-05-22 , Ahmad S. , Zolkefli M.Z.F. , Lajis M.A. , Haw H.F. , Talib N. , Kiow L.W. , Suhaimi Illias , Karim F.

Malaysia is one of the countries that produced thousands of plastics wastes every year. The research aims to develop sustainable bricks with thermosetting plastic waste. As part of the sand replacement, 15 brick samples were prepared and mixed with different melamine-formaldehyde (MF) content percentages. MF's style substitutions are 5%, 10%, and 15% whereas conventional bricks can be bought at the nearest shop. Three testing were conducted to measure the performances of sustainable sand brick in comparison with the conventional sand brick. The Bricks containing 15% MF demonstrated the best hybrid configuration in the testing process. Compared with other modified bricks and conventional bricks, the 15% MF bricks always displayed a higher positive value in every test performed. It shows the favor value of density, water absorption, and compressive strength test.

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